USA TODAY - Now is about the time you've got Las Vegas fatigue. For the sake of your sanity, you turn your attention to other things, lighter things.

Now is about the time survivors of that attack are beginning to feel the shock subside and an onslaught of emotions — anguish, grief, guilt — take over.

"There's national recognition and solidarity around these big events, (but) that sense of attention and care and compassion seems to fade with the next news cycle," said Seth Gillihan, a psychologist and Post-Traumatic Stress Disorder researcher. "The country pretty quickly returns to its baseline."

But survivors can't return to their baseline. Those who escaped the bullets can go home, and the injured will leave the hospital, but they can't go back to the lives they had.

"The world they knew before it happened is profoundly changed," Gillihan said. "They're probably going to have a different way of seeing the world, they may have a different way of seeing themselves, they may be critical of themselves for how they reacted during the event."

Las Vegas survivors have been thrust onto a new trajectory, one that will feel worse before it gets better. They are joining an unfortunate fellowship of those who've endured trauma — but one that can at least provide guidance down this too well-trodden path.

"I am just numb right now," said Justin Zimmerman, who hit the ground.

If you've watched interviews with the Las Vegas survivors, you might be amazed by their poise, but those who've dealt with trauma personally or professionally say this is what the initial aftershock looks like: numbness.

"If I'm being quite frank, the shock part was probably the easiest," said Brandon Wolf, who survived the Pulse nightclub shooting that killed 49 in Orlando in June 2016. "I was almost machine-like in preparing for the funerals, in talking to the media and politicians. The despair hadn't set in yet."

People react this way because they've experienced "more than the nervous system can process at once," Gillihan said.

"Most people who've gone through something this horrifying will have symptoms that look like PTSD initially. It's only when they continue to linger that a diagnosis would be given," Gillihan said.

Though rates of PTSD vary depending on the trauma, Gillihan said he would expect a "high percentage" to experience it in this case.

"Survivors of sexual assault, for example, the majority will develop PTSD, and I wouldn't be surprised if that were the case for this as well," Gillihan said.

While a mass shooting is obviously different from sexual assault or a natural disaster or combat, "we have one stress system and so it responds to different things in common ways," Gillihan said. Part of the reason he would expect high rates has to do with the "interpersonal" nature of this attack.

"It's something that was so unpredictable, senseless and intentional ... when it's done by a person, not a natural event, it adds another layer of trauma."

This is how it persists

Whether or not a trauma survivor is diagnosed with PTSD, they may share a number of these feelings and experiences after the fact:

"I was really, really confident as a person before June 12. I didn't struggle with crowded spaces, I was always the life of the party," Wolf said.

Now, that is lost. "I immediately look for an exit when I'm in a crowded room. I get a tight chest if I'm in a space I can't find a way out of. Sometimes I'm more afraid to sleep than I am to be awake because the things I dream about are really scary," he said. "And you don't know what to do. You seek therapy, you talk to people about it, but it's like you're trapped in your own mind."

Knowing this, experiencing this, Wolf said, is why his "heart breaks" for the Las Vegas survivors. Just as he described a number of situations that "set him off," Vegas survivors may experience similar triggers, Gillihan said, including:

Large crowds (Avoiding crowds is "almost a universal response" after trauma, Gillihan said.) Concerts News reports on violence or disasters ("It's not tragedy porn anymore, it's too painful," Wolf said.) Loud noises, such as a car backfiring Gun shots on TV shows and movies But survivors won't need a trigger to have the memory.

"Part of the haunting quality of PTSD is that these memories live with us," Gillihan said. "The memory can come up uninvited without any obvious triggers and these memories will just run through as your mind tries to process and make sense of them."